We propose to make use of existing small angle X-ray scattering (SAXS) facilities at SSRL to carry out studies of protein folding intermediates encountered in mutants of staphylococcal nuclease and in the a subunit of tryptophan synthase. The studies push the limits of available technology both in terms of the time scale of kinetic experiments and in quality of the signal desired in the equilibrium experiments, where we hope to do quantitative analysis on samples containing mixtures of species. In particular we hope to use the new broad band pass multilayer recently tested on beamline 4-2 to increase intensity and decrease exposure times.